Hi Thomas, > > However with a DPDK solution it would be possible to re-use the message bus > > to pass information like device stats, application state, D-state requests > > etc. to the host and allow for management layer(e.g. OpenStack) to make > > informed decisions. > > I think that management informations should be transmitted in a management > channel. Such solution should exist in OpenStack.
Perhaps it does, but this solution is not exclusive to OpenStack and just a potential use case. > > > Also, the scope of adding power management to qemu/KVM would be huge; > > while the easier path is not always the best and the problem of power > > management in VMs is both a DPDK problem (given that librte_power only > > worked on the host) and a general virtualization problem that would be > > better solved by those with direct knowledge of Qemu/KVM architecture > > and influence on the direction of the Qemu project. > > Being a huge effort is not an argument. I agree completely and was implied by what followed the conjunction. > Please check with Qemu community, they'll welcome it. > > > As it stands, the host backend is simply an example application that can > > be replaced by a VMM or Orchestration layer, by using Virtio-Serial it has > > obvious leanings to Qemu, but even this could be easily swapped out for > > XenBus, IVSHMEM, IP etc. > > > > If power management is to be eventually supported by Hypervisors directly > > then we could also enable to option to switch to that environment, currently > > the librte_power implementations (VM or Host) can be selected dynamically > > (environment auto-detection) or explicitly via rte_power_set_env(), adding > > an arbitrary number of environments is relatively easy. > > Yes, you are adding a new layer to workaround hypervisor lacks. And this layer > will handle native support when it will exist. But if you implement native > support now, we don't need this extra layer. Indeed, but we have a solution implemented now and yes it is a workaround, that is until Hypervisors support such functionality. It is possible that whatever solutions for power management present themselves in the future may require workarounds also, us-vhost is an example of such a workaround introduced to DPDK. > > > I hope this helps to clarify the approach. > > Thanks for your explanation. Thanks for the feedback. > > -- > Thomas Alan.
